In seven years as chief executive of Chicago public schools, Arne Duncan has supported a range of measures to shake up the status quo in urban education, including new charter schools, performance pay and tough accountability for struggling schools.

But he has also gained a reputation for reaching out to the teachers union and the community, helping to neutralize some potential critics and win allies.

Now, Duncan will take his political skills and reform zeal from the country's third-largest school system to Washington to become the next education secretary, a post that will require him to try to bridge deep divides among education advocates, labor leaders and civil rights groups over how to fix U.S. schools.

Yesterday, President-elect Barack Obama introduced Duncan as his nominee at a news conference at a Chicago school. "When it comes to school reform, Arne is the most hands-on of hands-on practitioners," Obama said at Dodge Renaissance Academy, adding: "When faced with tough decisions, Arne doesn't blink."

With Duncan at the helm of the 408,000-student system, test scores have improved, participation in Advanced Placement classes has risen sharply and graduation rates have edged up. However, the trade publication Education Week this year reported that the city's on-time graduation rate was 51 percent for the Class of 2005, ranking it behind most of the country's 50 largest school systems.

"While there are no simple answers," Duncan said at the event, "I know from experience that when you focus on basics like reading and math, and when you embrace innovative new approaches, and when you create a professional climate to attract great teachers, you can create great schools."

Under Duncan's leadership, charter schools were expanded, and a performance-pay plan was launched with the blessing of teachers. He supports a program to bring people into teaching who have little classroom experience but strong academic backgrounds. In 2006, he called on Congress to double funding for the No Child Left Behind law.

Duncan's résumé appeals to some who identify themselves as reformers, but his calls for increased funding and his willingness to partner with teachers also win the approval of unions and school officials who think the federal government imposes too many sanctions without offering enough support.

"Duncan is someone we believe can work with everyone, and that's going to be an important part of setting a new tone to get things done in the new administration, instead of treading water," said Joe Williams, executive director of the New York-based Democrats for Education Reform.

Duncan, 44, has close ties to Obama and has helped shape his education platform. During Obama's time in Illinois, they visited schools in Chicago but also bonded over pickup basketball. (Duncan co-captained Harvard University's team and played professionally in Australia for a few years.)

Across the spectrum of education advocates, Duncan wins praise from many quarters. Education Secretary Margaret Spellings called him "a visionary leader and fellow reformer who cares deeply about students."

National Education Association President Dennis Van Roekel, head of the country's largest teachers union, noted Duncan's push for increased funding and flexibility: "For too long, federal education policy has been about teaching to the test, and Duncan could use his new position to move beyond those failed policies and provide every child with 21st-century skills."

Duncan will take over the Education Department at a pivotal time. Efforts to revamp the 2002 No Child Left Behind Law, which aims to boost achievement of children from poor families, have been on hold as Congress awaits the new president. But many educators and lawmakers from both major parties have soured on the law, which requires states to rate schools on test scores. Teachers unions and some school officials have begun to see it as too rigid and punitive.

Obama has promised to "fix the failures" of the education law, but hammering out details will not be easy. He has pledged to improve testing and create a more nuanced way to hold schools accountable. But some of the law's advocates, including civil rights groups that applaud the spotlight on minority student performance, worry that the law could be watered down.

Duncan's challenge will be to help lawmakers and advocates reach agreement, said Michael J. Petrilli, who was associate assistant deputy secretary in the Education Department from 2001 to 2005 under President Bush and now works at the Thomas B. Fordham Foundation, an education think tank.

"This confirms what we know, that President-elect Obama has reform instincts, but he's also a diplomat and is careful to not alienate key constituencies in the Democratic Party and across the aisle," Petrilli said. "That's going to be a delicate balance -- to walk the line between the reform camp and the education establishment."

In Chicago, some Duncan-backed initiatives have met with resistance from teachers and parents. There has been some opposition to the city's move to shutter low-performing schools and reopen them with new staff.

But he is also known as an approachable, even humble, leader. In October, he choked up as he turned down an award given to him by an anti-gun group, saying too many Chicago students had been killed and he had "not earned it."

Debra Strauss, president-elect of the Illinois PTA, recalled meeting Duncan at his office to talk about how to harness the work of community organizations to engage parents and provide them with better services. She said Duncan met her at the door, shook her hand and introduced himself as Arne.

"He's sort of a roll-up-your-sleeves-and-get-down-to-work kind of individual," Strauss said. "He brings a very down-to-earth perspective."

Tom Loveless, director of the Brown Center on Education Policy at the Brookings Institution, said the choice of Duncan shows that Obama values the perspective of an on-the-ground educator.

"The message is that he wanted someone who has the respect of the field," Loveless said. "These are modest reforms, nothing way out of the mainstream, but pragmatic, and they seem to be working."